How do you determine for a filter to fit your monitor?

Answer:

Filters (if they provide them anymore) are sold by monitor sizes, usually in inches.



If you know your monitor size (ie: 17", 19", etc) afterwards it's a simple matter of choosing a filter i.e. suitable for that size. If you don't know the size of your monitor, check on the sticker on the back of the monitor and you'll find the size surrounded by the description. Otherwise, take a cassette measure and means the screen size diagonally (ie: top gone to bottom right corners) in inches, and you can undamagingly assume the nearest value to be the monitor size.
Measure the eyeshade diagonally top R/hand corner to bottom L/hand corner